In brief
For a week in Japan with maps, messages and social media every day, our calculator estimates about 5.4 GB: the 10 GB plan, at €8.60, covers it. Maps and messages alone use about 0.2 GB a day, so 3 GB is enough for 10 days. Daily video adds about 1 GB a day: aim for 20 GB or more. Run short? Top up in the app.
Key points
- A week of maps, messages and social media comes to about 5.4 GB: the 10 GB plan covers it.
- Maps, messages and browsing use about 0.2 GB a day; video adds about 1 GB a day.
- Streaming, video calls and sharing your connection are what eat through data fastest.
- Your plan starts at your first connection in Japan, not when you buy it.
- Running low? Top up from the app or from your account on the website.
How much for 7, 10 or 14 days
Find your trip length, then the column closest to how you use your phone. Each cell shows the estimated data, then the smallest Mobile Companion plan that covers it.
| Trip | Maps and messages | Plus social media | Plus social media and video |
|---|---|---|---|
| 7 days | About 1.5 GB: 3 GB plan, €3.10 | About 5.4 GB: 10 GB plan, €8.60 | About 13.1 GB: 20 GB plan, €14.60 |
| 10 days | About 2.2 GB: 3 GB plan, €3.10 | About 7.7 GB: 10 GB plan, €8.60 | About 18.7 GB: 20 GB plan, €14.60 |
| 14 days | About 3.1 GB: 5 GB plan, €4.80 | About 10.8 GB: 20 GB plan, €14.60 | About 26.2 GB: 50 GB plan, €28.90 |
These are the figures our calculator uses: about 0.2 GB a day for maps, messages, e-mail and browsing, plus 0.5 GB a day for social media and 1 GB a day for video, with a small safety margin on top. They’re rough estimates: a heavy video day can use far more.
Data use by activity
Text is light, photos use more, and video uses by far the most, especially when it plays by itself in your social feeds. Here’s roughly what each activity adds to a day in Japan.
| Activity | Per day | Good to know |
|---|---|---|
| Maps, messages, e-mail and browsing | About 0.2 GB | Offline maps downloaded on Wi-Fi save even more. |
| Social media | About 0.5 GB more | Videos that play by themselves use most of it. |
| Video calls on WhatsApp or FaceTime | About 0.3 GB more | They use your data, not your UK calls allowance. Turning off the camera cuts it. |
| Video and streaming | About 1 GB more | See Netflix’s own figures below. |
| Sharing your connection (hotspot) | About 0.5 GB more | A laptop can use far more through updates and cloud sync. |
| Photo and video backups | Heavy | Automatic uploads can run in the background: pause them until you’re on Wi-Fi. |
What Netflix says about video
Video is one activity where an app publishes clear figures. According to Netflix’s help centre, checked on 17 October 2026, this is the most data one hour of streaming uses on one device, for each of its data usage settings:
| Netflix setting | Video quality | Data per hour |
|---|---|---|
| Low | Basic | Up to 0.3 GB |
| Medium | Standard | Up to 0.7 GB |
| High | Standard definition | Up to 1 GB |
| High | High definition (HD) | Up to 3 GB |
| High | Ultra HD (4K) | Up to 7 GB |
So one hour a day at the Medium setting is up to 0.7 GB, or up to 7 GB over a 10-day trip for the films alone. On a phone screen, a lower quality setting often looks fine.
Work it out for your trip
Your trip doesn’t fit the table? Choose how long you’re staying and what you’ll do on your phone: the calculator estimates the data you need and suggests the smallest plan that covers it.
You’ll need about
7.7 GB
7.7 GB of 10 GBYou’ll have 2.3 GB left
Suggested plan10 GB · 30 days
€8.60
A rough estimate. You can top up from the app at any time.
Your plan has to cover your whole stay, and it starts at your first connection in Japan, not when you buy it: here’s when your plan starts. Between two sizes? You can top up later from the app, so you don’t have to buy for the worst case.
Ways to use less data
- Download offline maps on Wi-Fi. Google Maps lets you save an area and use it offline, where available. Public transport and walking directions still need a connection, though (Google Maps Help).
- Use Wi-Fi when you have it. At your hotel, for example, for app updates, big downloads and photo backups.
- Download before you go out. Many streaming apps let you save episodes, films or playlists on Wi-Fi to enjoy later.
- Turn on your phone’s low-data mode. On iPhone, Low Data Mode turns off Background App Refresh and automatic downloads and backups (Apple Support). On Android, Data Saver lets most apps use background data only on Wi-Fi (Google help).
- Stop videos playing by themselves. Many social apps have a setting to turn off autoplay on mobile data.
- Check WhatsApp’s settings. Under Storage and data, you can choose which photos and videos download automatically on mobile data.
- Prepare your laptop before you share. Pause automatic updates and cloud sync before you connect it to your phone’s hotspot. Sharing your connection is allowed with Mobile Companion.
Run out? Top up in the app
If your data runs low, top up from the Mobile Companion app or from your account on the website, and carry on. The app shows how much data you’ve used, so you can see it coming, and it has a home-screen widget.
Prices are shown in euros. If you pay with a UK card, your bank converts the amount into pounds and may charge a fee for it. Still comparing? Our Japan eSIM price comparison puts other brands side by side, with the date of each price.
Ready to choose? Our plans run from €1.20 for 1 GB to €28.90 for 50 GB: see them all in Japan eSIM plans by data and length of stay.
Ready to go?
Online as soon as you land
Your eSIM on NTT docomo’s 5G network, installed in 1 minute before you fly. From €1.20.
See the plansFAQ
How much data do I need in Japan for 2 weeks?
With maps, messages and social media every day, our calculator estimates about 10.8 GB, so the 20 GB plan (€14.60) covers it. Maps and messages only: about 3.1 GB, just over 3 GB, so the 5 GB plan (€4.80). Add daily video and you’re looking at the 50 GB plan.
How much data do I need for a week in Japan?
About 5.4 GB with social media every day: the 10 GB plan, at €8.60. If you mostly use maps and messages, it’s about 1.5 GB, so the 3 GB plan (€3.10) is enough.
How much data does Google Maps use?
Much less than video or social media: maps, messages and browsing together come to about 0.2 GB a day. Offline maps downloaded on Wi-Fi cut it further, although public transport and walking directions still need a connection.
Does using my phone as a hotspot use more data?
Yes: count about 0.5 GB more a day, and far more if a laptop runs updates or cloud sync. Sharing your connection is allowed with Mobile Companion.
What if I run out of data?
Top up from the Mobile Companion app or from your account on the website, and carry on. The app shows how much data you’ve used, so you can see it coming.
